The importance of early intervention to minimize the handicapping effects of hearing impairment makes early diagnosis desirable. Unfortunately, the widespread screening of neonates has been hampered by the lack of sufficiently robust, reliable and cost-effective tools, and by the relatively low prevalence of hearing impairment in this population. The central goal of this multi-center collaborative application is to obtain a large unbiased database containing information about the stimulus-response characteristics of three physiologic responses related to hearing status - transient evoked otoacoustic emissions (TOAE), acoustic distortion product emissions (ADP) and auditory brainstem responses (ABR) - in normal-hearing and hearing-impaired neonates. Four thousand eight hundred (4800) NICU infants and 2400 normal well-baby nursery infants will be evaluated at six sites using ABR, TOAE and ADP. Neonatal hearing status will be validated by behavioral responses to auditory stimuli at 8-12 months corrected age. The accuracy of each tool for identifying neonatal hearing impairment, as validated by visual reinforcement audiometry, will be determined using methods based on signal detection theory. The primary measure of accuracy will be the area under the receiver operating characteristic (ROC) curve. ROC analysis provides a description of disease detectability that is independent from both disuse prevalence and decision threshold effects. These data will be used to design screening protocols with known accuracy and costs as a function of target population and setting. Prototype model systems will be developed and evaluated. Ultimately, these data in concert with modem technology, can be used to design inexpensive, intelligent devices to implement universal screening for hearing impairment. The influence of age and medical status on the performance of TOAE, ADP and ABR in identifying peripheral hearing impairment, as well as the cost of implementation and cost-effectiveness will also be evaluated.